Reusable medication delivery device

ABSTRACT

A medication injection or delivery system is provided for injecting fluids such as insulin within body tissue. The device includes a housing, a flexible shaft movably mounted within the housing, and a dose setting mechanism for controlling the movement of the shaft with respect to a fluid-containing cartridge removably positioned within or mounted to the housing. The flexible shaft, according to exemplary embodiments, includes a plunger and a flexible cable connected to the dose setting mechanism. The plunger and dose setting mechanism are connected together by the flexible shaft. The dose setting mechanism, in one aspect of the invention, includes a screw, a locking mechanism, and a nut assembly connected to the flexible shaft. The dose setting mechanism is used to set the dosage and prime the catheter. The plunger retracts into a recess to permit a new cartridge to be installed quickly.

This application is a continuation of Application No. 09/672,103, filedon Sep. 29, 2000 now U.S. Pat. No. 6,482,186.

The present application is related to and claims priority under 35U.S.C. §119 to U.S. application Ser. No. 60/156,535, filed Sep. 29,1999, U.S. application Ser. No. 60/170,570, filed Dec. 13, 1999, andU.S. application Ser. No. 60/177,762, filed Jan. 24, 2000, the entirecontents of each of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to devices for delivering a predeterminedamount of a substance to a patient, and more particularly to a manualmedication delivery device. The present invention also relates tomethods of use and kits including such devices.

2. Brief Description of the Related Art

There are many medical conditions that require the administration ofliquid medicaments transcutaneously (through the skin) for prolongedperiods. Diabetes, for example, may be controlled by daily, or morefrequent, injections of insulin. The ability to administer numeroussmall dosages of insulin has been proven to be the best way to insuretight glucose control for a patient. The National Institutes of Health(NIH) conducted a long-term study of people with diabetes known as theDiabetes Complications and Control Trial (DCCT) were it was determinedthat the proper management of diabetes requires 4 or more injections ofinsulin per day. However, current devices either are not convenient oreasy to use by patients. Syringes and insulin pens all require thepatients to inject themselves and do not provide a convenient ordiscreet mechanism to accomplish medication delivery.

Since transcutaneous injections are painful and troublesome, and sinceeach injection represents a possibility for infection, injections arespaced at intervals as far apart as possible, resulting in peak andvalley concentrations of the medicament in the bloodstream or at thesite in the body requiring the medicament, the peak concentrationsoccurring shortly after the administration of the medicament and thelow, or valley, concentrations occurring shortly before theadministration of the next injection. This method of administrationexposes the patient to the possibility of overdose at peak levels andunderdose at valley levels, but was nevertheless the standard method formany years in the absence of a better alternative.

Recently, systems have been developed in which a catheter issemi-permanently implanted in a patient to provide access to atranscutaneous site in a patient's body, and a liquid medicament issupplied to the catheter from a reservoir. Insigler and Kirtz(Diabetics, 28: 196-203, 1979) describe a portable insulin dosageregulating apparatus which uses an electrically driven mini-pump with aninsulin reservoir to periodically dispense a predetermined number ofinsulin units (U). A small electronic control box is used to set thebasal rate of 0.4 U/hr in stages of 0.2 U each. A switch is used totrigger a program that infuses a higher dose for a period of one hour,after which the system automatically goes back to the basal rate.

U.S. Pat. No. 3,963,380, issued Jun. 15, 1976, to Thomas et al.,describes a micropump driven by piezoelectric disk benders. Although thepump draws only a small current, it requires a voltage of about 100volts to drive the pump. Tamborlane et al. (The New England Journal ofMedicine, 300: 573-578, No. 11, Mar. 15, 1979) describe a portablesubcutaneous insulin delivery system which uses a battery driven syringepump. The apparatus is bulky and heavy.

A peristaltic motor driven pump has been described by Albisser et al.(Med. Progr. Technol. 5: 187-193 [1978]). The pump weighs 525 g. andconsumes 60 milliwatts at maximum pumping rates. This system has acontinuous duty cycle. It is bulky and heavy and consumes a relativelylarge amount of power.

The pump devices that are currently commercially available require thepatient to use a very intensive therapy that includes basal rateapplication of medication and periodic bolus injections. This type oftherapy means the patient with diabetes must test their glucose levelsto monitor and change the basal rate infusion and the bolus injections.This requires the patient to test frequently by lancing their finger andusing expensive test strips to determine their glucose levels.

The inconvenience and difficulty needed to use current devicesillustrates the need for a better mechanism to provide medicationdelivery for patients. This is especially true for those patients thathave diabetes who are required to provide regular injections of insulinto treat their disease. In addition, the current problems that haverecently been associated with oral medications will make thesimplification of injection technology important for these patients whowill be placed on insulin therapy to treat their disease since thecurrent oral drugs are being removed from the market place.

SUMMARY OF THE INVENTION

According to a first exemplary embodiment, a portable infusion devicecomprises a housing having a cavity, a first opening into the cavity,and a second opening into the cavity, the cavity having a curvedportion, an elongate flexible member, the flexible member beingpositioned at least in part in the curved portion, the flexible memberbeing substantially axially incompressible and laterally flexible, andwhereby, when a medication ampule including a piston is positionedadjacent to the first opening, the flexible member can be advancedthrough the curved portion of the cavity to push against and move theampule piston without substantially compressing the flexible member.

According to a second exemplary embodiment, a portable infusion devicecomprises a housing having a proximal end, a distal end, a sidewallextending longitudinally between said proximal end and said distal end,an opening formed in at least one of said sidewall, said proximal end,and said distal end, and an interior cavity, an ampule positioned insaid housing interior cavity, said ampule including a distal end havinga sealed outlet, a piston in said ampule, and said ampule sized andconfigured to pass through said housing opening, a catheter having aproximal end, a distal end, and at least one lumen extending betweensaid proximal end and said distal end, said catheter proximal end beingreleasably attached to one of said housing distal end and said ampuledistal end, a longitudinally movable plunger positioned in said housingfor engaging with and distally moving said ampule piston, manuallymovable dosage selection means, including interior portions positionedin said housing and selectively engaging said plunger, manually movableexterior portions positioned exterior of said housing for permitting auser of said portable infusion device to select a plunger traveldistance, and a manually engageable element connected to said interiorportions to move said plunger said plunger travel distance when saidinterior portions engage said plunger.

According to a third exemplary embodiment, a method of injecting amedication into a patient comprises the steps of providing a portableinfusion device comprising a housing having a cavity, a first openinginto the cavity, and a second opening into the cavity, the cavity havinga curved portion, and an elongate flexible member, the flexible memberbeing positioned at least in part in the curved portion, the flexiblemember being substantially axially incompressible and laterallyflexible, positioning a medication ampule including a piston adjacent tothe first opening, positioning a tube in fluid communication with themedication ampule and subcutaneously in a patient, advancing theflexible member through the curved portion of the cavity, pushingagainst and moving the ampule piston without substantially compressingthe flexible member to dispense medication from the ampule, through thetube, and into the patient.

Still other objects, features, and attendant advantages of the presentinvention will become apparent to those skilled in the art from areading of the following detailed description of embodiments constructedin accordance therewith, taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention of the present application will now be described in moredetail with reference to preferred embodiments of the apparatus andmethod, given only by way of example, and with reference to theaccompanying drawings, in which:

FIG. 1 illustrates an exploded perspective view of a first exemplaryembodiment of a device according to the present invention;

FIG. 1a illustrates a cross-sectional view of the device of FIG. 1;

FIG. 2 illustrates portions of a device in accordance with the presentinvention;

FIG. 3 illustrates a cross-sectional view of another embodiment inaccordance with the present invention;

FIG. 4 illustrates an end elevational view of portions of the device ofFIG. 3;

FIG. 5 illustrates a cross-sectional view of yet another embodiment inaccordance with the present invention;

FIG. 6 illustrates a perspective view of yet another embodiment inaccordance with the present invention; and

FIG. 7 illustrates a cross-sectional view taken at line 7—7 in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

One advantage of capability of alternately using a catheter or a penneedle is unique to the invention because of the compact size,non-twisting attachment design, and positive adjustment capability. Whenthe patient uses a catheter, the occurrence of infection and irritationis reduced because the medication, e.g., insulin, does not continuouslyenter the subcutaneous site. The patient can also use the device in amanner similar to currently available injection pens to delivery insulinwhen they do not want to use a catheter, thereby increasing theconvenience of the device. By combining bolus therapy, catheter aideddelivery, pen tip delivery, sanitary cartridge utilization, a reductionof injection site irritation, compact size, and the ability to selectthe method of delivery on a day-to-day basis, the patient is given manyadvantages by devices and methods of the present invention.

In general, a medication injection or delivery system is provided forinjecting fluids such as insulin within body tissue. The device includesa housing, a flexible shaft movably mounted within the housing, and adose setting mechanism for controlling the movement of the shaft withrespect to a fluid containing cartridge removably positioned within ormounted to the housing. The flexible shaft, according to exemplaryembodiments, includes a plunger and a flexible cable connected to thedose setting mechanism. The plunger and dose setting mechanism areconnected together by the flexible shaft. The dose setting mechanism, inone aspect of the invention, includes a screw, a locking mechanism, anda nut assembly connected to the flexible shaft. The dose settingmechanism is used to set the dosage and prime the catheter. The plungerretracts into a recess to permit a new cartridge to be installedquickly.

The injection device includes elements threadably engaging the nutassembly to adjust the dosage of medication. According to other aspectsof the present invention, a spring axially connected to the dosagesetting nut is positioned so as to move the dosage setting nut when thebrake assembly releases the flexible shaft connected to the nut assemblyand the plunger. The dosage setting nut assembly that is engaged to thescrew is stopped when the bottom of the dosage setting nut assemblycomes into contact with stops on the housing or case. The device furtherincludes elements for securing to the housing a cartridge containingfluid. The device alternatively does not have a spring connected withthe dosage setting nut and the injection is accomplished by the patientmanually providing pressure on the adjusting knob to inject themedication.

According to certain aspects of the invention, the flexible shaft isconstructed of materials that can transmit both tension and compression.However, the flexible shaft should be capable of transmitting the forcesaround bends and curves, which insures that the device can be compactand discrete. The flexible shaft is capable of transmitting both tensionand compression and also capable of being clamped by an external brakewithout the shaft being collapsed. The flexible shaft transmits theforces without axial deflection which would otherwise result inerroneous injection amounts. An outer spring provides compressionresistance and an inner tube provides the ability for the spring neitherto collapse when the brake is applied nor to distort when loaded axiallyin compression because it does not allow the windings to overlap eachother when captivated in the guide tube. The cable provides the tensionresistance for the flexible shaft assembly.

While it is contemplated that the present invention will utilize astandard insulin cartridge, holding 100-200 insulin units in a 1.5-3.0milliliter volume, the present invention is not so limited, and can beresized and reconfigured to be used with medication cartridges orampules of any size.

The ability to provide a small, discreet injection device that iscapable of being used with both a catheter and an injection needleprovides a significant advantage for the patient who must injectthemselves on a regular basis, such as a person with diabetes. Thepatient can configure the device with a catheter on those occasionswhere discreet injection is needed, such as at work or other publicsituations. The catheter is then inserted subcutaneously and themedication is injected by setting the dosage mechanism and releasing ormanually injecting the dosage. The catheter can be left in the patientfor up to three days and thereby eliminates the need to insert a needleinto themselves again over the three day period.

Devices of the present invention can have a small size and compactshape, which can allow the patient to wear it or hide it in theirclothes so that it is not obvious to the people around them. Thealternate configuration of being used with a conventional pen tipprovides a means for the patient to use the same device to injectthemselves when they do not want to use a catheter. The ability to usethe device with two injection methods is unique and made possible by thesystem use of bolus therapy and the small and compact size.

The DCCT determined that the proper management of diabetes requires 4 ormore injections of insulin per day. Currently, however,insulin-dependent diabetics rarely observe this critical treatmenttherapy because of the difficult and indiscreet nature of the currentinsulin delivery methods. All the available devices require the patientto carry the device and insulin, and inject in public. Those patientsthat use insulin pumps are afforded a more discreet means of infusion,but because of the basal rate therapy, require that they test theirglucose levels 7 to 10 times a day. The present invention does notchange the method of treatment but facilitates the delivery of insulinby providing a dual methodology to delivery the insulin that isselectable by the patient. They can either use a catheter or a pen-tipto deliver the required dosage of insulin. By creating a dual modemedication delivery device for the administration of a medicament, suchas insulin, to a patient in small, controlled doses over an extendedperiod the patients therapy is improved while maintaining a continuitywith their existing means of treatment.

Referring to the drawing figures, like reference numerals designateidentical or corresponding elements throughout the several figures.

FIG. 1 illustrates an exploded perspective view of a first exemplaryembodiment of a device according to the present invention. The deviceincludes elements for holding a medication ampule 70 so that it can beconnected to a medication delivery tube of the user's choice, a housing1 including elements for transmitting force to the piston 71 of theampule, and elements with which the user can select a dosage ofmedication for delivery from the device and manually or automaticallyinitiate administration of the medication. One aspect of the presentinvention is the provision of a force transmitting member which caneffectively transmit force from dosage selection and manualadministration elements along a non-linear path to the piston of themedication ampule, thus permitting the device as a whole to beconstructed, and the constituent elements thereof arranged, in compactways. The force transmitting member transmits the force without axialdeflection, which would otherwise reduce dosage accuracy.

Turning back to FIG. 1, a sleeve 99 includes a hollow interior sized toreceive a medication ampule 70 therein through an opening 98 b in acylindrical extension 98 of the sleeve. The sleeve 99 preferably istransparent or translucent and preferably includes dosage indiciathereon so that the user may visually inspect the contents of the ampulevial and determine the amount of medication therein. The extension 98includes an upstanding peg 98 a set back from the opening 98 b. The peg98 a cooperates with a circumferential groove 101 e formed on theinterior of a slip collar 100. When the slip collar is slipped over theextension 98 with the peg 98 a extending through a longitudinal slot 101d in the sidewall 101 a of the slip collar, the peg may enter the groove101 e. With the peg in the circumferential groove, the slip collar 100can be rotated, securing the slip collar to the extension 98 againstlongitudinal movement.

The cooperation of slip collar 100 and extension 98 permits a needleholding device, described below, to be placed in and secured between theslip collar and the extension. While many needle holding devices arewithin the spirit and scope of the present invention, exemplaryembodiments will now be described. For example, a subcutaneous infusionset 800 can be secured between the slip collar 100 and the extension 98to fluidly communicate the interior of the medication ampule 70 with asubcutaneous needle 800 a on the distal end of the subcutaneous set 800.The proximal end of the set 800, as will be readily appreciated by oneof ordinary skill in the art, includes a needle or other septum piercingelement 815 with an associated hub 805 at the proximal end of the set.The hub 805 has an outer diameter smaller than the interior diameter ofthe slip collar 100, yet larger than the inner diameter of a distalopening 101 b of the slip collar, so that he slip collar will hold thehub and piercing element 815 in place. The piercing element 815 has alength and diameter so that when the hub 805 and piercing element 815are retained by the slip collar 100 within the hollow interior of theextension 98, the piercing element pierces the septum 72 at the distalend of the medication ampule 70. Thus, the slip collar 100 and extension98 secure the proximal end of the set 800 to the ampule 70 and place thesubcutaneous needle 800 a in fluid communication with the interior ofthe ampule through the septum 72. The hub 805 applies a sufficientpressure to the septum 72 when engage to the septum to minimizedeformation of the septum when the piston 71 is engaged.

Instead of subcutaneous set 800, the subcutaneous injection setdescribed in Attorney Docket No. 032994-013, 09/675,159 filed Sep. 29,2000, entitled “Subcutaneous Injection Set for Use with a Reservoir thathas a Septum”, Joel Douglas et al., which is incorporated by referenceherein, can be used. Further optionally, the adapter described inAttorney Docket No. 032994-017, 09/672,097 filed Sep. 29, 2000, entitled“Pen Needle Assembly and Adapter”, Joel Douglas et al, which isincorporated by reference herein, can be used. Also optionally, theadapter described in Attorney Docket No. 032994-019, 09/672,456 filedSep. 29, 2000, entitled “Micro Infusion Device”, Joel Douglas et al,which is incorporated by reference herein, can be used.

An advantage of the present invention is that, when used with anadministration set which includes a length of tubing, such as tubing 800b, between a piercing element and the needle (e.g., needle 800 a) whichis inserted into the user, the tubing can effectively act as a strainrelief for the junction of the piercing element 815 and the septum 72,the junction of the needle 800 a and the user's skin, or both. Thus, theseptum 72 is less prone to be distorted by the piercing element 815, andthus can increase the accuracy of the dosage administered and assist inmaintaining the sterility of the contents of the medication ampule 70.Similarly, the user's skin is less prone to be pulled during injection,which can improve the user's comfort levels.

The exemplary device illustrated in FIG. 1 includes a housing 1 that hasan interior cavity 5 that accommodates a flexible shaft 40. The flexibleshaft 40 will be described in greater detail below and with reference toFIGS. 2 and 3. Flexible shaft 40 is slidably movable in the cavity 5 sothat it can extend out of the housing in order to push on the piston 71of the ampule 70, and in this manner acts as a plunger for the piston.The flexible shaft is constructed so that it is capable of transmittingforce to the piston 71 to expel medication from the ampule 70, but theflexible shaft is also flexible so that it can be used in a bentconfiguration. The provision of the flexible shaft therefore enables thedesign of the housing of devices according to the present invention tobe more compact than traditional “pen-type” injectors, while allowingaccurate injections to be made, because axial deformation of theflexible shaft is minimized.

The housing 1 includes openings 2 and 3 that lead to the cavity 5. Afitting 130 is positioned in the opening 2, and includes a hollowinterior 130 c, a cylindrical body 130 b, and an annular flange 130 a onone end of the fitting. As can be seen in FIG. 1, the hollow interior130 c is sized so that the flexible shaft 40 can slide through thefitting 40. The fitting is secured to the housing by, e.g., glue,ultrasonic welding, a screw 4, or the like.

A brake mechanism 25 is also optionally provided to permit a user of thedevice to releasably hold the flexible shaft 40 from advancing into theampule and dispensing medication. A seat 36 is formed or positioned inthe housing 1, and includes a transverse hole 35 through the housing. Agenerally D-shaped brake shoe 26 includes a threaded hole 26 a and atubular extension 26 b which is received in the hole 35 with someclearance so that the extension can rotate in the hole. The housing 1includes a transverse opening 6 which can be closed by a cover 31 havinga hole 31 a. A threaded bolt 27 with a head 29 is threaded through thecover's hole 31 a and into the threaded hole 26 a. A cover 28 is securedto the back side of the housing to cover the other side of hole 35. Aknob 300 having ears 300 a is secured to the head 29 to permit a user torotate the bolt, and therefore the brake shoe 26. The shoe 26 isconfigured so that the upon rotation about an axis extending throughhole 26 a and bolt 27, the outer curved portion 26 c is rotated outfarther away from the hole 26 a and engages and presses against theouter surface of the flexible shaft 40. Further rotation of the shoe 26causes the shoe to press against the flexible shaft 40 with a forcesufficient to hold the shaft in place from displacement along the lengthof the shaft. Rotation of the shoe 26, by rotation of the knob 300, inthe opposite direction disengages the curved portion 26 c from theflexible shaft 40, permitting the shaft to move.

The device also includes a set of elements which permit the user of thedevice to set a medication dosage and drive the flexible shaft 40 todispense and administer that dosage. For ease of illustration in FIG. 1,some portions of the flexible shaft 40 have been removed from theillustration, but it is to be understood that the embodiment of theflexible shaft illustrated and described herein extends continuouslybetween a plunger end attached to plunger 60 and another, opposite endsecured to nut 95.

The nut 95 includes partial threads 95 a on the top of the nut, and isconnected to the flexible shaft 40, e.g., by a swag 63. The threads 95 ado not extend all the way around the nut, but rather are only present ona portion so that the nut can engage and disengage with a sleeve 105, asdescribed in greater detail below. The nut therefore can includesidewalls 95 b which are sized and configured so as not to mate with theinterior threaded surface 105 b of the sleeve 105. According to oneaspect of the present invention, the nut 95 is attached to a tensioncable 67, which forms a part of the flexible shaft, described in greaterdetail below. The nut 95 is positioned in the sleeve 105 and the sleevecan rotate around the nut when the threads of the nut and sleeve areengaged. The pitch of threads 95 a is selected so that a desiredfraction or number of rotations of sleeve 105 relative to nut 95corresponds to a desired dosage of medication dispensed from the ampule70. As will be readily appreciated by one of ordinary skill in the art,threads 95 a can be single or multistart threads.

The sleeve 105 includes, as discussed above, a hollow interior 105 c andhas an interior surface which includes threads 105 b to mate with theexterior threads on nut 95. As better illustrated in FIG. 1a, the sleeve105 optionally further includes slits 152, 153 through the wall of thesleeve. The slits 152, 153 define a tab or finger 112 which can flexaway from the nut 95, thus disengaging the threads of the sleeve 105 andthe nut 95. Deflection of the tab or finger 112 allows a user to push onplunger 60 to retract the nut 95 in sleeve 105. The exterior surface ofthe sleeve 105 also preferably includes one or more equallycircumferentially spaced, longitudinally extending grooves 154, 155,156. When the slits 152, 153 are provides, they act as additionalgrooves and are preferably equally spaced with the grooves 154, 155,156. When the slits 152, 153 are not provided, additional grooves areprovided in their places. The grooves and slits cooperate with one ormore small pins or similar protuberances 151 to generate an audibleclick, a tactile snap, or both, when the sleeve 105 is rotated withinthe housing 1. Preferably, the number and spacing of the grooves 154,155, 156 is selected along with the pitch of the threads 95 a, 105 b sothat the circumferential distance between the grooves corresponds to aknown portion of a desired dosage. By way of example and not oflimitation, threads 95 a, 105 b and the circumferential spacing ofgrooves 154, 155, 156 can be selected together so that one unit ofmedication from ampule 70 is dispensed for each audible/tactile clickgenerated by the interaction of pins 151 and the grooves.

A dosage knob or dial 150 is secured to the outer end 105 a of thesleeve 105 so that rotation of the knob 150 rotates the sleeve. Whenassembled (see, e.g., FIG. 3), the knob 150 is outside of the housing 1,while the sleeve 105 moves in and out of the cavity 5 through theopening 3. A motion limiting element 120 is positioned in the sleeve 105and partially around the nut 95. In the exemplary embodiment illustratedin FIG. 1, the motion limiting element takes the form of a split shafthaving a longitudinally extending slot 120 a that extends transverselythrough the shaft. The slot 120 a can be, for ease of assembly, open atthe end 120 b of the shaft. The transverse width of the shaft 120 isselected to be smaller than the internal diameter of the sleeve 105 inwhich the shaft is positioned so as not to interfere with the rotationof the sleeve relative to the nut 95. The dimensions of the slot 120 aare selected so that the nut 95, as well as the flexible shaft 40secured to the nut 95, can move longitudinally along the shaft withoutthe shaft interfering with this movement. The length of the slot 120 ais selected, however, so that the closed end 120 c of the slot 120prevents the nut 95 from being backed out of the sleeve 105. Furtherpreferably, the length of the slot 120 a is selected to correspond tothe maximum dosage amount that it is desired to dispense from ampule 70.For example, the length of the slot 120 a can be selected to be apreselected percentage of the total distance that piston 71 can travelin ampule 70, up to 100% of the travel distance. As illustrated betterin FIG. 3, the length of the flexible shaft 40 is selected so that thenut 95 is positioned adjacent to the closed end 120 c when a new ampuleis installed in the device.

A second retaining sleeve 107 is also positioned in the cavity 5. Thesleeve 107 is mounted in the housing 1 so that an open outer end 107 cof the sleeve is adjacent to the opening 3. The sleeve 107 includes ahollow interior 107 a. The inner end of the sleeve 107 includes anopening through which the flexible shaft 40 extends which is delimitedby a stop 107 b. An insert 160 is mounted in the stop 107 b. The insert160 includes flats 160 a which are sized to receive the end 120 b of theshaft 120, and the shaft is secured to the insert. The insert alsoincludes a hollow interior 160 b through which the flexible shaft 40extends.

According to yet another embodiment of the present invention, thehousing 1 can further include a recess 202 adjoining that portion of thecavity 5 which contains the sleeve 107. A cylindrical locking member 200is rotatably positioned in the recess 202. The member 200 includes aflat exterior portion 201 a, a cylindrical exterior portion 201 b, and akeyhole, recess, or the like 201 in the external face of the member. Thesleeve 107, in this additional embodiment, includes a cutout portion 107d on that portion of the sleeve which faces the recess 202. Recess 202,member 200, and cutout portion 107 d are provided to cooperate with tab112, as described in greater detail below, to permit rapid retraction ofthe flexible cable 40 and nut 95.

Turning now to FIG. 2, one embodiment of the flexible shaft 40 isillustrated with portions broken away. According to the embodimentillustrated in FIG. 2, the flexible shaft 40 includes an outer flexiblespring 3000, an intermediate flexible tube 3010 positioned inside thespring 3000, and an inner tension cable 3020 positioned inside the tube3010. The outer diameter of the intermediate tube 3010 is preferablyselected to be slightly smaller than the inner diameter of the spring3000 so that the tube supports the spring along its entire length, whilepermitting the spring and tube together to bend without kinking. Thetube 3010 also prevents the spring windings from overlapping oneanother. The inner tension cable 3020, which corresponds to element 67in FIG. 1, extends between the plunger 60 and the nut 95. The cable 3020is secured to the plunger 60, such as by screw 64, and to nut 95, as bythe swag 63. The tension cable 3020, through the plunger 60 and the nut95, prevents the spring 3000 from extending, yet is flexible to alsobend and flex with the spring and the tube 3010 to transmit force alonga linear or non-linear path to the piston 71 of the ampule 70 withoutaxial deformation.

According to one embodiment, the flexible shaft 40 includes a springsegment available from Century Spring of Los Angeles, Calif., modelE-12, which has a wire size of at least 0.035 and an outer diameterwinding width of 0.25 inches. The intermediate tube can be formed of aPVC tube with an outer diameter of 0.176 inches and inner diameter of0.100 inches. A stainless steel cable of 0.035 inches outer diameter isthreaded through the PVC tube and used to place the assembly undercompression.

The operation of the embodiments illustrated in FIGS. 1, 1 a, and 2 willnow be described with reference thereto and to FIG. 5, which illustratesa cross-sectional view of the assembled device. FIG. 5 illustrates thedevice and an ampule 70 positioned therein prior to the administrationof medication from the ampule, and with the flexible shaft 40 completelyretracted. The user locks the flexible shaft 40 by rotating the knob300. The user than rotates the knob 150, which rotates the sleeve 105.Audible and/or tactile clicks are produced by rotation of the sleeverelative to the housing 1. As the sleeve 105 is rotated, the sleeve 105moves out of the housing 1 while the nut 95 remains stationary. In thismanner, the sleeve is backed out of the housing a distance which relatesto, and is preferably the same as, the distance that the piston 71 willbe moved.

When the user has backed out the sleeve 105 the desired amount, aspreferably indicated by the audible and/or tactile clicks, or by visualinspection, the user turns the knob 300 to unlock the flexible shaft 40and to permit it to move. The user then presses on the flat face 150 aof the knob, which pushed the sleeve 105 in toward the housing. Becausethe threads 105 b of the sleeve 105 mate with the threads 95 a of thenut 95, and the nut is secured to the flexible shaft 40, the nut 95 isdriven along with the sleeve toward the housing. This movement of thenut 95 and sleeve 105 continues while the user presses on the face 150a. The flexible shaft 40 pushed by the nut 95 through the cavity 5 andthrough the fitting 130. The plunger 60 on the plunger end of theflexible shaft 40 pushes against the piston 71 of the ampule 70, whichin turn expels medication from the ampule. The ampule 70 is held in thedevice by split collar 100, and therefore the force generated by theuser against face 150 a is transmitted through the sleeve 105, nut 95,flexible shaft 40, and plunger 60 to the piston 71.

As the flexible shaft 40 is free to move along its own length in thecavity 5, but restrained from buckling by the housing 1, the directionof the user-generated force is changed but still transmitted to thepiston. Upon completion of the desired administration, the knob 150 isagain adjacent to the housing 1, as illustrated in FIG. 5. The entiredevice can then conveniently be placed in a carrying case, handbag,pocket, or wherever the user desires, while permitting the subcutaneousset 800 to remain in place inconspicuously attached to the infusiondevice.

When the user desires to administer another volume of medication fromthe ampule 70, the plunger 60 is still in position against the piston 71from the previous administration. The nut 95 is in a position betweenthe end 120 c and the end 120 b of the shaft 120, having been moved as aresult of the prior advancement of the flexible shaft 40. The knob 150is again rotated, backing out the sleeve 105, and the flexible shaft 40is again advanced through the housing 1 to push the piston 71.

Devices according to the present invention function to preserve theinformation of how much of the medication a user desires to dispensefrom the ampule, even when there less than this amount contained in theampule installed in the device. That is, devices according to thepresent invention have a memory aspect which retains information abouthow much of a dosage is left to be administered even if the ampule mustbe changed to complete the administration. By way of example, if theuser backs out the sleeve 105 a distance which corresponds to theadministration of 10 units of medication, but the position of the piston71 in the ampule only will permit 7 units of medication to be dispensed,the sleeve 105 and flexible shaft 40 will only travel the distance todispense the 7 units. Thus, the knob 150 will not be moved up to housing1, and the user will have an indication that the entire desired dosagehas not been administered. By providing the device with a dosageindicator, described in greater detail below, the user can see how muchadditional medication must be administered for a complete dosage. Theuser can load a new ampule into the device, dial out an appropriatesupplemental dosage amount, and complete the dosage administration.

When the flexible shaft 40 has been moved so that the nut 95 is againstthe insert 160, the shaft must be retracted to reset the device. Thiscan be accomplished several ways. The knob 150 can be retracted fully,pulling the nut with it, and then the knob 150 rotated to advance thesleeve 105 into the housing while the nut 95 remains stationary. Theprovision of locking member 200, recess 202, and cutout 107 d permitsanother way of resetting the device. A tool 113 is provided whichincludes an end which can be inserted into recess 201 a to rotate thelocking member 200 in the recess 202. The knob 150 is pulled out as faras it will, which retracts the nut 95 and the flexible shaft 40. Theknob 150 is then rotated so that an indicator, such as flat 150 bopposite and aligned with slot 120 a, shows that the tab 112 is adjacentto and aligned with the cutout 107 d and recess 202. The tool 113 isthen used to rotate the locking member 200 in recess 202 so that theflat 201 a is aligned with and adjacent to the tab 112. Thus, the tab isno longer restrained against radial movement, and can deflect outward inresponse to relative movement of the nut 95. The knob 150 is then pushedin, which causes the sleeve 105 to move in toward the housing. Becausethe tab 112 is aligned with the cutout 107 a and the flat 201 a, the tabcan deflect outward, disengaging the threads 105 b from the threads 95 aof the nut 95. The sleeve 105 therefore moves inward relative to the nut95, with the result that the nut moves to a position closer to end 105 aof the sleeve. If the nut 95 is not yet adjacent to the end 105 a, thisprocess can be repeated to move the sleeve 105 and nut 95 relative toeach other to reset the device.

FIGS. 3 and 4 illustrate yet another embodiment in accordance with thepresent invention. The device illustrated in FIGS. 3 and 4 is similar insome respects to those illustrated in FIGS. 1-2, and therefore only thedifferences between them will be described herein. The embodiment ofFIGS. 3 and 4 include structures which provide an automatic injectionfunction. The housing 1 includes the cavity 5 having an additional space4000 radially outside the space in which the sleeve 105 extends. Thesleeve 105 includes an annular shoulder 4110 which slides in the space4000. A spring 4080 is also positioned in the space 4000 between theshoulder 4110 and a shoulder 4090 of the housing which delimits thespace.

FIG. 4 illustrates an end view of the shoulder 4110. The sleeve 105includes portions 4010 which act as spring cams against the innersurface 4100 of that portion of the housing which defines the space4000. Thus, friction is developed between the housing and the shoulder4110. According to another aspect of the invention, the profile of thesurface 4100 is slightly tapered so that the frictional force betweenthe shoulder and the surface changes.

In operation, the device illustrated in FIGS. 3 and 4 is used in amanner very similar to that described above with respect to FIGS. 1-2.When the sleeve 105 is backed out the desired amount, the spring 4080 iscompressed, and exerts a force in the direction of arrow 4070 againstthe sleeve 105 through the shoulder 4110. When the user wants to deliverthe dosage, the knob 300 is rotated, unlocking the flexible shaft 40.The spring 4080 pushes against the shoulder 4110, driving the sleeve105, nut 95, and flexible shaft 40 as described above. The frictionbetween the shoulder 4110 and the surface 4100, which acts against themotion of the sleeve in the direction opposite the arrow 4070, slows thesleeve 105. The taper of the surface 4100 and the elasticity of thespring cams 4010, generated by the normal force 4020 of the spring camsagainst the surface 4100, cause the frictional force to change over thetravel of the shoulder 4110, thus regulating the speed of the injection.Preferably, the surface 4100 is tapered so that the frictional force ishigher at the beginning of the injection stroke and less toward the endof the injection stroke.

FIG. 5 illustrates other aspects of the present invention, and portionsof the elements illustrated in FIG. 5 have been described elsewhereherein. FIG. 5 also illustrates another embodiment of a device foradministering the dosage to the user, a pen needle 900. Pen needlesusable in the present invention are currently commercially available,for example a Novofine® 30⅓ inch (8 mm) pen needle (Novo Nordisk,Princeton, N.J.). As illustrated in FIG. 5, the pen needle 900 includesa needle 902 for piercing the septum 72, a needle 904 for insertionsubcutaneously into the patient in fluid communication with the needle902, and a cylindrical shroud or cover 906 which covers the needle 902.The shroud 906 is placed over the septum 72, which pushes the tip of theneedle 902 into the interior of the ampule 70. The split collar 100 isplaced over the pen needle 900, securing it in place. A cap or cover 908covering the needle 904 is then removed, the needle inserted into theuser, and the dosage can be delivered to the user.

FIG. 6 illustrates yet another embodiment of a device in accordance withthe present invention. The device illustrated in FIG. 6 is similar insome respects to other embodiments described herein. The device includesa mechanism 700 which permit the user of the device to establish a zeroset point on a scale, so that the user can then set a proper dosageamount for administration. A sleeve 705 is mounted around the outer endof the sleeve 105 (see FIG. 1) and includes a set of numbers printed onthe external surface of the sleeve 705. The sleeve 705 includes an outerring 708 which is adjacent to a ring 704 on the dosage setting knob 703(which corresponds to knob 150) of the sleeve 105. The rings 704 and 708include mating structures, such as complementary teeth, so that when therings are held together, they will rotate together without slipping. Aspring 702 is positioned between the rings 704 and 708 to bias the outersleeve 705 outward so that the rings abut each other. The outer sleeveextends into the housing 1 through which, with the aid of a magnifyingglass type window 706, the user can view the numbers printed on theexterior of the sleeve 705. The spacing of the numbers on the sleeve 705is selected so that a relatively large angular rotation 701 of thedosage setting knob 703 is matched with the appropriate distance oflinear motion 707 of the sleeves 705, 105.

To use the zero scale, the user pushes the outer sleeve 705 in towardthe housing against the force of the spring 702, disengaging thecomplementary structures on the rings 704, 708. The outer sleeve 705 canthen be freely rotated until a zero appears in window 706. The user thenreleases the sleeve, which returns to its position with the rings 704,708 next to each other. The user can then manipulate the dosage knob 703to back out sleeve 105, which carries with it sleeve 705 because of theengagement of rings 704 and 708. Therefore, the outer sleeve 705 isrotated and moved further out of the housing 1, moving the appropriatenumber printed on the exterior of sleeve 705 beneath window 706 for theuser to verify that the dosage knob has been set to administer thecorrect dosage.

FIGS. 6 and 7 illustrate yet a further embodiment of the presentinvention. A side injection actuator 600 is movably mounted to the sideof the housing 1, and is connected (see FIG. 7) to portions of thesleeve 105. The actuator 600 includes a scale indicator 603 which alignswith a scale 601 printed on the exterior of the housing. As illustratedin FIG. 7, which illustrates a partial cross sectional view through thehousing at line 7—7, the housing includes a slot 607 in which aconnecting arm 613 slides. The arm 613 connects together the actuator600 and a ring 611 which is received in the same space as the spring 609(corresponding to spring 4080). As will be readily appreciated by one ofordinary skill in the art, spring 609 and the automatic injectionfeature can be optionally removed. The ring 611 abuts against anoutwardly extending shoulder 605, similar to shoulder 4110, formed onsleeve 105.

The side injection actuator 600 moves along with sleeve 105 as thesleeve is backed out of the housing 1 when the user sets a dosage amountwith dosage knob 150 or 703, because the ring 611 is pushed linearlybackward by the shoulder 605. As the ring 611 and shoulder 605 are notattached, however, the rotation of shoulder 605 as the sleeve 105 isbacked out does not cause the ring 611 to rotate. Once the user has seta dosage amount, the user can choose between pushing on the dosage knob150 or 703, or pushing the side injection actuator forward along thehousing toward the position illustrated in FIG. 7. The scale 601 andscale indicator 603 provide a visual check for the user that the dosageamount has correctly been set.

While the invention has been described in detail with reference topreferred embodiments thereof, it will be apparent to one skilled in theart that various changes can be made, and equivalents employed, withoutdeparting from the scope of the invention. Each of the foregoingreferences and documents are incorporated by reference herein in each oftheir entireties.

What is claimed is:
 1. A portable infusion device comprising: a housinghaving a cavity, a first opening into the cavity, and a second openinginto the cavity, the cavity having a curved portion; an elongateflexible member, the flexible member being positioned at least in partin the curved portion, the flexible member being substantially axiallyincompressible and laterally flexible; whereby, when a medication ampuleincluding a piston is positioned adjacent to the first opening, theflexible member can be advanced through the curved portion of the cavityto push against and move the ampule piston without substantiallycompressing the flexible member; an ampule holder having a cavity sizedto receive an ampule therein, a first opening into the ampule holdercavity, and a second opening into the ampule holder cavity, the ampuleholder second opening positioned adjacent to the housing first opening;and a collar sized to receive a first portion of the ampule holder inthe collar the ampule holder first positioned including the ampuleholder first opening, wherein the collar is a split collar having aninterior surface, a slot, and a groove on the interior surface, and theampule holder includes an upstanding peg sized to be received in thegroove.
 2. A portable infusion device comprising: a housing having acavity, a first opening into the cavity, and a second opening into thecavity, the cavity having a curved portion; and an elongate flexiblemember, the flexible member being positioned at least in part in thecurved portion, the flexible member being substantially axiallyincompressible and laterally flexible; whereby, when a medication ampuleincluding a piston is positioned adjacent to the first opening, theflexible member can be advanced through the curved portion of the cavityto push against and move the ampule piston without substantiallycompressing the flexible member, wherein the elongate flexible membercomprises: an outer flexible member; and an intermediate flexible memberpositioned inside the outer flexible member.
 3. An infusion device inaccordance with claim 2, wherein the outer flexible member and theintermediate flexible member are not connected to each other alongsubstantially their entire lengths.
 4. An infusion device in accordancewith claim 2, wherein the outer flexible member and the intermediateflexible member each include first and second end and are attached toeach other at their first and second ends, respectively.
 5. An infusiondevice in accordance with claim 2, further comprising an inner flexiblemember positioned inside the intermediate flexible member, the innerflexible member being substantially axially inextensible.
 6. A portableinfusion device comprising: a housing having a cavity, a first openinginto the cavity, and a second opening into the cavity, the cavity havinga curved portion; an elongate flexible member, the flexible member beingpositioned at least in part in the curved portion, the flexible memberbeing substantially axially incompressible and laterally flexible;whereby, when a medication ampule including a piston is positionedadjacent to the first opening, the flexible member can be advancedthrough the curved portion of the cavity to push against and move theampule piston without substantially compressing the flexible member,further comprising: a dosage sleeve at least partially positioned in thehousing cavity and movable out of the housing second opening, the dosagesleeve including a hollow interior and an interior surface havingthreads; and a nut including an outer surface, a part of the nut outersurface including threads sized and configured to mate with the dosagesleeve threads, the nut attached to one end of the elongate flexiblemember; whereby rotation of the sleeve relative to the nut moves thesleeve away from the elongate flexible member.
 7. An infusion device inaccordance with claim 6, wherein the dosage sleeve further comprises: anexterior surface including a plurality of longitudinally extendinggrooves; and wherein the housing includes at least one peg sized andpositioned to engage the dosage sleeve exterior surface and produce aclick when the dosage sleeve is rotated.
 8. An infusion device inaccordance with claim 6, wherein the dosage sleeve includes an inner endinside the cavity and an outer end, and wherein the flexible member hasa length so that when the nut is adjacent to dosage sleeve outer end asecond end of the flexible member is immediately adjacent to the housingfirst opening.
 9. An infusion device in accordance with claim 6, whereinthe dosage sleeve further comprises an annular shoulder positioned atthe dosage sleeve inner end, wherein the housing further comprises ashoulder adjacent to the dosage sleeve, and further comprising a springpositioned between the dosage sleeve shoulder and the housing shoulder,the spring being compressed when the dosage sleeve moves out of thehousing.
 10. An infusion device in accordance with claim 6, wherein thedosage sleeve further comprises a friction surface, wherein the housingfurther comprises a friction surface bearing against the dosage sleevefriction surface, and wherein the housing friction surface is configuredand arranged so that the friction generated between the housing frictionsurface and the dosage sleeve friction surface is not constant as thedosage sleeve moves out of the housing.
 11. An infusion device inaccordance with claim 6, further comprising: a zero set sleevepositioned around a portion of the dosage sleeve, the zero set sleevebeing rotatable on the dosage sleeve and including an annular ring; azero set spring; wherein the dosage sleeve include an annular ring atthe dosage sleeve outer end; wherein the zero set spring is positionedbetween the zero set sleeve annular ring and the dosage sleeve annularring to bias the zero set sleeve and the dosage sleeve together.
 12. Aninfusion device in accordance with claim 11, wherein the zero set sleeveincludes an outer surface and dosage indicia on the zero set sleeveouter surface; and further comprising a window through the housing, thezero set sleeve dosage indicia being visible through the window.
 13. Aninfusion device in accordance with claim 6, further comprising a slot inthe housing, an annular ring positioned around the dosage sleeve, an armconnected to the annular ring and extending through the slot, and a sideinjection actuator attached to the arm outside of the housing, whereinpushing on the side injection actuator pushes the dosage sleeve.
 14. Aninfusion device in accordance with claim 6, wherein the dosage sleevefurther comprises an inner end, an outer end, and a pair of slotsextending longitudinally from the dosage sleeve inner end, the pair ofslots forming a finger from a portion of the dosage sleeve; wherein thehousing cavity further comprises a recess adjacent to the housing secondopening; and further comprising a locking member rotatably positioned inthe recess, the locking member having a non-uniform exterior surfaceincluding first and second portions; whereby when the locking member ispositioned with the first portion immediately adjacent to the dosagesleeve finger, the first portion prevents the finger from flexingradially outward, and when the locking member is positioned with thesecond portion immediately adjacent to the dosage sleeve finger, thesecond portion permits the finger to flex radially outward.
 15. Aninfusion device in accordance with claim 1, further comprising a lockingcam movably mounted in the housing cavity, the cam positioned adjacentto the elongate flexible member, the locking cam being movable between afirst orientation in which the locking cam does not interfere withmovement of the flexible member in the cavity, and a second orientationin which the locking cam presses against the flexible member an inhibitsmovement of the flexible member in the cavity.